The invention relates to charging for message communication, e.g. short messages, in intelligent network applications and especially to charging for message communication by a prepaid subscriber. A prepaid subscriber refers to a subscriber using prepaid subscription, i.e. a subscriber who has paid in advance.
A large number of different services can be offered to a subscriber of a telecommunication network—a wire network or a mobile network, for instance—by means of an intelligent network (IN). Examples of the services are a virtual private network (VPN) service, which enables the use of private numbers, and a personal number service, in which the intelligent network reroutes calls made to the personal number in a manner controlled by the subscriber.
An example of message communication in mobile networks is the short message service SMS. It differs from speech and data services in that to send a short message, a connection from the sender to the receiver need not be established, since short messages are transmitted through signalling. For instance, in the pan-European GSM network (Global System for Mobile Communication), short messages can be received and sent even during an ongoing call, since short messages are transmitted on control channels.
Charging an intelligent network subscriber for intelligent network services is usually done when the subscriber makes a call. In other words, establishing a connection triggers the charging. On the other hand, an intelligent network subscriber can also use chargeable short message services, for instance send short messages. Some systems also charge for receiving short messages. A connection is, however, not established for a short message service, in which case the intelligent network charging is not triggered, because prior art switching centres supporting intelligent network services do not support charging an intelligent network subscriber for short messages. The matter becomes especially problematic when prepaid connection time is used, because sending short messages, for instance, does not reduce the amount of money available, only actual calls do.